Haley Joel Osment celebrated his 12th birthday on the set during the last day of shooting. Although Kevin Spacey and Helen Hunt had completed their own filming, they turned up on the set just to celebrate his birthday. Coincidentally, Trevor McKinney, the character played by Osment, celebrates his 12th birthday in the movie.
In the scene where Helen Hunt's character strikes her son Trevor across the face, Haley Joel Osment requested that she actually hit him to make it seem more realistic. However, director Mimi Leder declined.
In the book, the teacher is a black man named Reuben St. Clair. The role of Reuben was originally offered to Denzel Washington but was turned down, due to other commitments. When Kevin Spacey agreed to the movie, the character was changed to a white man named Eugene Simonet.